1. Field of the Invention
The invention broadly relates to grinders and sharpeners for blades and chisels.
2. Prior Art
A wood working blade, such as a chisel blade or a plane blade, includes a beveled front end and a flat back which must both be perfectly flat. The flatness of the beveled front end is particularly important for a plane blade, because even a slightly curved surface will prevent the sharp edge from making full contact with the work piece. The back must also be perfectly flat at least at the front end to cooperate with the beveled front end to make a straight cutting surface.
Woodworking blades are often sharpened with the rim of a grinding wheel. However, the grinding wheel makes a concave cutting edge which weakens the edge. Therefore, Japanese tools should never be sharpened with a grinding wheel. Another type of grinding platen provides a flat side for grinding. However, the high rotation rate of several hundred r.p.m. may heat the blade enough to lose its temper. Also, it is very difficult to hold the blade by hand at the correct angle to grind a perfectly flat surface. Any wobbling will result in a curved surface on the blade. Further, lubricant used on the platen may be flung outward towards the user and the surrounding area.